METHOD FOR PREPARING POWER LITHIUM BATTERY DIAPHRAGM

摘要

The present invention relates to the field of lithium battery technologies, and particularly to a method for preparing a power lithium battery diaphragm. The method comprises steps such as dissolving, assistant adding, extruding, sheeting casting, diaphragm forming by drawing, and shaping, and a polyolefin resin microporous membrane, namely a lithium battery diaphragm, is obtained finally. The thickness of the diaphragm prepared by the method of the present invention ranges from 10 mum to 25 mum, the preferential porosity of the diaphragm ranges from 40% to 70%, and the heat shrinkage rate at 105 °C is below 5%. The diaphragm prepared by the method of the present invention has low closed-pore temperature, high fusing temperature, low heat shrinkage rate, and good mechanical properties and has excellent safety performance when used as a power lithium battery diaphragm. In addition, the power lithium battery diaphragm of the present invention is a polyethylene microporous single-layer thin film which has good heat stability after being subjected to processes such as drawing and shaping.